Method and apparatus for receiving extended access barring parameters in wireless communication system

ABSTRACT

A method and apparatus for receiving extended access barring (EAB) parameters in a wireless communication system is provided. A user equipment (UE) receives an EAB parameter, and receives an EAB parameter modification. The received EAB parameter is invalidated upon receiving the EAB parameter modification. The UE also waits for applying EAB until modified EAB parameter is received, and receives the modified EAB parameter.

This application is a continuation of, and claims priority to, U.S.patent application Ser. No. 15/342,552 filed Nov. 3, 2016, which iscontinuation of Ser. No. 14/429,652 filed Mar. 19, 2015 (now issued asU.S. Pat. No. 9,516,576), which is a National Stage Entry ofInternational Application No. PCT/KR2013/008667 filed Sep. 27, 2013, andclaims priority to U.S. Provisional Application No. 61/706,743 filedSep. 27, 2012, all of which are hereby incorporated by reference intheir entireties as if fully set forth herein.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to wireless communications, and moreparticularly, to a method and apparatus for receiving extended accessbarring (EAB) parameters in a wireless communication system.

Related Art

Universal mobile telecommunications system (UMTS) is a 3rd generation(3G) asynchronous mobile communication system operating in wideband codedivision multiple access (WCDMA) based on European systems, globalsystem for mobile communications (GSM) and general packet radio services(GPRS). A long-term evolution (LTE) of UMTS is under discussion by the3rd generation partnership project (3GPP) that standardized UMTS.

Extended access barring (EAB) is a mechanism for the operator(s) tocontrol mobile originating access attempts from UEs that are configuredfor EAB in order to prevent overload of the access network and/or thecore network. In congestion situations, the operator can restrict accessfrom UEs configured for EAB while permitting access from other UEs. UEsconfigured for EAB are considered more tolerant to access restrictionsthan other UEs. When an operator determines that it is appropriate toapply EAB, the network broadcasts necessary information to provide EABcontrol for UEs in a specific area.

How to apply EAB parameters upon connection establishment should beclarified.

SUMMARY OF THE INVENTION

The present invention provides a method for receiving extended accessbarring (EAB) parameters in a wireless communication system. The presentinvention provides how a user equipment (UE) applies EAB parameters upona connection establishment.

In an aspect, a method for receiving, by a user equipment (UE), extendedaccess barring (EAB) parameters in a wireless communication system isprovided. The method includes receiving an EAB parameter, and receivingan EAB parameter modification. The received EAB parameter is invalidatedupon receiving the EAB parameter modification. The method includeswaiting for applying EAB until modified EAB parameter is received, andreceiving the modified EAB parameter.

The EAB parameter and the modified EAB parameter may be received via asystem information block (SIB)-14 message.

The EAB parameter modification may be received via a paging message.

The method may further include applying EAB according to the modifiedEAB parameter.

The method may further include waiting for establishing a radio resourcecontrol (RRC) connection until the modified EAB parameter is received.

The UE may be in an RRC idle state.

The modified EAB parameter may be received without waiting until nextsystem information modification period boundary.

In another aspect, a user equipment (UE) in a wireless communicationsystem is provided. The UE includes a radio frequency (RF) unit fortransmitting or receiving a radio signal, and a processor coupled to theRF unit, and configured to receive an EAB parameter, receive an EABparameter modification. The received EAB parameter is invalidated uponreceiving the EAB parameter modification. The processor is configured towait for applying EAB until modified EAB parameter is received, andreceive the modified EAB parameter.

UE behaviors for applying EAB parameters upon a connection establishmentmay be clarified.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a structure of a wireless communication system.

FIG. 2 is a diagram showing radio interface protocol architecture for acontrol plane.

FIG. 3 is a diagram showing radio interface protocol architecture for auser plane.

FIG. 4 shows an example of a physical channel structure.

FIG. 5 shows transmission of a paging channel.

FIG. 6 shows a change of change of system information.

FIG. 7 shows a system information acquisition procedure.

FIG. 8 shows an RRC connection establishment procedure.

FIG. 9 shows an example of a method for receiving EAB parametersaccording to the conventional art.

FIG. 10 shows an example of a method for receiving EAB parametersaccording to an embodiment of the present invention.

FIG. 11 is a block diagram showing wireless communication system toimplement an embodiment of the present invention.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

The technology described below can be used in various wirelesscommunication systems such as code division multiple access (CDMA),frequency division multiple access (FDMA), time division multiple access(TDMA), orthogonal frequency division multiple access (OFDMA), singlecarrier frequency division multiple access (SC-FDMA), etc. The CDMA canbe implemented with a radio technology such as universal terrestrialradio access (UTRA) or CDMA-2000. The TDMA can be implemented with aradio technology such as global system for mobile communications(GSM)/general packet ratio service (GPRS)/enhanced data rate for GSMevolution (EDGE). The OFDMA can be implemented with a radio technologysuch as institute of electrical and electronics engineers (IEEE) 802.11(Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, evolved UTRA (E-UTRA), etc.IEEE 802.16m is evolved from IEEE 802.16e, and provides backwardcompatibility with a system based on the IEEE 802.16e. The UTRA is apart of a universal mobile telecommunication system (UMTS). 3^(rd)generation partnership project (3GPP) long term evolution (LTE) is apart of an evolved UMTS (E-UMTS) using the E-UTRA. The 3GPP LTE uses theOFDMA in a downlink and uses the SC-FDMA in an uplink. LTE-advanced(LTE-A) is an evolution of the LTE.

For clarity, the following description will focus on LTE-A. However,technical features of the present invention are not limited thereto.

FIG. 1 shows a structure of a wireless communication system.

The structure of FIG. 1 is an example of a network structure of anevolved-UMTS terrestrial radio access network (E-UTRAN). An E-UTRANsystem may be a 3GPP LTE/LTE-A system. An evolved-UMTS terrestrial radioaccess network (E-UTRAN) includes a user equipment (UE) 10 and a basestation (BS) 20 which provides a control plane and a user plane to theUE. The user equipment (UE) 10 may be fixed or mobile, and may bereferred to as another terminology, such as a mobile station (MS), auser terminal (UT), a subscriber station (SS), a wireless device, etc.The BS 20 is generally a fixed station that communicates with the UE 10and may be referred to as another terminology, such as an evolved node-B(eNB), a base transceiver system (BTS), an access point, etc. There areone or more cells within the coverage of the BS 20. A single cell isconfigured to have one of bandwidths selected from 1.25, 2.5, 5, 10, and20 MHz, etc., and provides downlink or uplink transmission services toseveral UEs. In this case, different cells can be configured to providedifferent bandwidths.

Interfaces for transmitting user traffic or control traffic may be usedbetween the BSs 20. The BSs 20 are interconnected by means of an X2interface. The BSs 20 are connected to an evolved packet core (EPC) bymeans of an S1 interface. The EPC may consist of a mobility managemententity (MME) 30, a serving gateway (S-GW), and a packet data network(PDN) gateway (PDN-GW). The MME has UE access information or UEcapability information, and such information may be primarily used in UEmobility management. The S-GW is a gateway of which an endpoint is anE-UTRAN. The PDN-GW is a gateway of which an endpoint is a PDN. The BSs20 are connected to the MME 30 by means of an S1-MME, and are connectedto the S-GW by means of S1-U. The S1 interface supports a many-to-manyrelation between the BS 20 and the MME/S-GW 30.

Hereinafter, a downlink (DL) denotes communication from the BS 20 to theUE 10, and an uplink (UL) denotes communication from the UE 10 to the BS20. In the DL, a transmitter may be a part of the BS 20, and a receivermay be a part of the UE 10. In the UL, the transmitter may be a part ofthe UE 10, and the receiver may be a part of the BS 20.

FIG. 2 is a diagram showing radio interface protocol architecture for acontrol plane. FIG. 3 is a diagram showing radio interface protocolarchitecture for a user plane.

Layers of a radio interface protocol between the UE and the E-UTRAN canbe classified into a first layer (L1), a second layer (L2), and a thirdlayer (L3) based on the lower three layers of the open systeminterconnection (OSI) model that is well-known in the communicationsystem. The radio interface protocol between the UE and the E-UTRAN canbe horizontally divided into a physical layer, a data link layer, and anetwork layer, and can be vertically divided into a control plane whichis a protocol stack for control signal transmission and a user planewhich is a protocol stack for data information transmission. The layersof the radio interface protocol exist in pairs at the UE and theE-UTRAN.

A physical (PHY) layer belonging to the L1 provides an upper layer withan information transfer service through a physical channel. The PHYlayer is connected to a medium access control (MAC) layer which is anupper layer of the PHY layer through a transport channel. Data istransferred between the MAC layer and the PHY layer through thetransport channel. The transport channel is classified according to howand with what characteristics data is transmitted through a radiointerface. Between different PHY layers, i.e., a PHY layer of atransmitter and a PHY layer of a receiver, data is transferred throughthe physical channel. The physical channel is modulated using anorthogonal frequency division multiplexing (OFDM) scheme, and utilizestime and frequency as a radio resource.

The PHY layer uses several physical control channels. A physicaldownlink control channel (PDCCH) reports to a UE about resourceallocation of a paging channel (PCH) and a downlink shared channel(DL-SCH), and hybrid automatic repeat request (HARQ) information relatedto the DL-SCH. The PDCCH can carry a UL grant for reporting to the UEabout resource allocation of UL transmission. A physical control formatindicator channel (PCFICH) reports the number of OFDM symbols used forPDCCHs to the UE, and is transmitted in every subframe. A physicalhybrid ARQ indicator channel (PHICH) carries an HARQ ACK/NACK signal inresponse to UL transmission. A physical uplink control channel (PUCCH)carries UL control information such as HARQ ACK/NACK for DLtransmission, scheduling request, and CQI. A physical uplink sharedchannel (PUSCH) carries a UL-uplink shared channel (SCH).

FIG. 4 shows an example of a physical channel structure.

A physical channel consists of a plurality of subframes in a time domainand a plurality of subcarriers in a frequency domain. One subframeconsists of a plurality of symbols in the time domain. One subframeconsists of a plurality of resource blocks (RBs). One RB consists of aplurality of symbols and a plurality of subcarriers. In addition, eachsubframe can use specific subcarriers of specific symbols of acorresponding subframe for a PDCCH. For example, a first symbol of thesubframe can be used for the PDCCH. A transmission time interval (TTI)which is a unit time for data transmission may be equal to a length ofone subframe.

A DL transport channel for transmitting data from the network to the UEincludes a broadcast channel (BCH) for transmitting system information,a paging channel (PCH) for transmitting a paging message, a DL-SCH fortransmitting user traffic or control signals, etc. The systeminformation carries one or more system information blocks. All systeminformation blocks can be transmitted with the same periodicity. Trafficor control signals of a multimedia broadcast/multicast service (MBMS)are transmitted through a multicast channel (MCH). Meanwhile, a ULtransport channel for transmitting data from the UE to the networkincludes a random access channel (RACH) for transmitting an initialcontrol message, a UL-SCH for transmitting user traffic or controlsignals, etc.

A MAC layer belonging to the L2 provides a service to a higher layer,i.e., a radio link control (RLC), through a logical channel. A functionof the MAC layer includes mapping between the logical channel and thetransport channel and multiplexing/de-multiplexing for a transport blockprovided to a physical channel on a transport channel of a MAC servicedata unit (SDU) belonging to the logical channel. The logical channel islocated above the transport channel, and is mapped to the transportchannel. The logical channel can be divided into a control channel fordelivering control region information and a traffic channel fordelivering user region information. The logical includes a broadcastcontrol channel (BCCH), a paging control channel (PCCH), a commoncontrol channel (CCCH), a multicast control channel (MCCH), a multicasttraffic channel (MTCH), etc.

An RLC layer belonging to the L2 supports reliable data transmission. Afunction of the RLC layer includes RLC SDU concatenation, segmentation,and reassembly. To ensure a variety of quality of service (QoS) requiredby a radio bearer (RB), the RLC layer provides three operation modes,i.e., a transparent mode (TM), an unacknowledged mode (UM), and anacknowledged mode (AM). The AM RLC provides error correction by using anautomatic repeat request (ARQ). Meanwhile, a function of the RLC layercan be implemented with a functional block inside the MAC layer. In thiscase, the RLC layer may not exist.

A packet data convergence protocol (PDCP) layer belongs to the L2. Afunction of a packet data convergence protocol (PDCP) layer in the userplane includes user data delivery, header compression, and ciphering.The header compression has a function for decreasing a size of an IPpacket header which contains relatively large-sized and unnecessarycontrol information, to support effective transmission in a radiosection having a narrow bandwidth. A function of a PDCP layer in thecontrol plane includes control-plane data delivery andciphering/integrity protection.

A radio resource control (RRC) layer belonging to the L3 is defined onlyin the control plane. The RRC layer takes a role of controlling a radioresource between the UE and the network. For this, the UE and thenetwork exchange an RRC message through the RRC layer. The RRC layerserves to control the logical channel, the transport channel, and thephysical channel in association with configuration, reconfiguration, andrelease of RBs. An RB is a logical path provided by the L2 for datadelivery between the UE and the network. The configuration of the RBimplies a process for specifying a radio protocol layer and channelproperties to provide a particular service and for determiningrespective detailed parameters and operations. The RB can be classifiedinto two types, i.e., a signaling RB (SRB) and a data RB (DRB). The SRBis used as a path for transmitting an RRC message in the control plane.The DRB is used as a path for transmitting user data in the user plane.

An RRC state indicates whether an RRC of a user equipment (UE) islogically connected to an RRC of an E-UTRAN. When an RRC connection isestablished between an RRC layer of the UE and an RRC layer of theE-UTRAN, the UE is in an RRC connected state (RRC_CONNECTED), andotherwise the UE is in an RRC idle state (RRC_IDLE). Since the UE inRRC_CONNECTED has the RRC connection established with the E-UTRAN, theE-UTRAN can recognize the existence of the UE in RRC_CONNECTED and caneffectively control the UE. Meanwhile, the UE in RRC_IDLE cannot berecognized by the E-UTRAN, and a core network (CN) manages the UE inunit of a tracking area (TA) which is a larger area than a cell. Thatis, only the existence of the UE in RRC_IDLE is recognized in unit of alarge area, and the UE must transition to RRC_CONNECTED to receive atypical mobile communication service such as voice or datacommunication.

When the user initially powers on the UE, the UE first searches for aproper cell and then remains in RRC_IDLE in the cell. When there is aneed to establish an RRC connection, the UE which remains in RRC_IDLEmay establish the RRC connection with the RRC of the E-UTRAN through anRRC connection procedure and then may transition to RRC_CONNECTED. TheUE which remains in RRC_IDLE may need to establish the RRC connectionwith the E-UTRAN when uplink data transmission is necessary due to auser's call attempt or the like or when there is a need to transmit aresponse message upon receiving the paging message from the E-UTRAN.

A non-access stratum (NAS) layer belongs to an upper layer of the RRClayer and serves to perform session management, mobility management, orthe like. To manage mobility of the UE in the NAS layer, two states,i.e., an EPS mobility management (EMM) registered state (EMM-REGISTERED)and an EMM deregistered state (EMM-DEREGISTERED), can be defined. Thetwo states are applicable to the UE and the MME. The UE is initially inEMM-DEREGISTERED. To access the network, the UE may perform a process ofregistering to the network through an initial attach procedure. If theinitial attach procedure is successfully performed, the UE and the MMEmay be in EMM-REGISTERED.

In addition, to manage a signaling connection between the UE and theEPC, two states, i.e., an EPS connection management (ECM) idle state(ECM-IDLE) and an ECM connected state (ECM-CONNECTED), can be defined.The two states are applicable to the UE and the MME. When the UE inECM-IDLE establishes an RRC connection with the E-UTRAN, the UE may bein ECM-CONNECTED. When the MME in ECM-IDLE establishes an S1 connectionwith the E-UTRAN, the MME may be in ECM-CONNECTED. When the UE is inECM-IDLE, the E-UTRAN does not have information on the context of theUE. Therefore, the UE in ECM-IDLE can perform a UE-based mobilityrelated procedure such as cell selection or cell reselection withouthaving to receive a command of the network. If a location of the UE inECM-IDLE becomes different from a location known to the network, the UEmay report the location of the UE to the network through a tracking areaupdate procedure. On the other hand, the mobility of the UE inECM-CONNECTED may be managed by the command of the network.

FIG. 5 shows transmission of a paging channel.

When there is data to be transmitted by a network to a specific UE or acall delivered to the specific UE, the paging message is used to searchand wake up the UE. To transmit the paging message, an E-UTRAN maysearch for a certain location area in which the UE is currently located,and may transmit the paging message through one cell belonging to thelocation area in which the UE is located. For this, whenever there is achange in the location area, the UE may report the change to thenetwork, which is called a location area update procedure.

Referring to FIG. 5, a plurality of paging cycles is configured, and onepaging cycle may include a plurality of paging occasions. When receivingthe paging message, the UE may perform discontinuous reception (DRX) todecrease power consumption. For this, the network may configure aplurality of paging occasions for every time period called a pagingcycle, and a specific UE may receive the paging message by monitoring apaging channel only during a specific paging occasion. The UE does notmonitor the paging channel in a time other than the specific pagingoccasion assigned to the UE. One paging occasion may correspond to oneTTI.

System information is described below. It may be referred to Section 5.2of 3GPP TS 36.331 V11.1.0 (2012-09).

System information is divided into a MasterInformationBlock (MIB) and anumber of SystemInformationBlocks (SIBs). The MIB includes a limitednumber of most essential and most frequently transmitted parameters thatare needed to acquire other information from the cell, and istransmitted on a BCH. SystemInformationBlockType1 contains informationrelevant when evaluating if a UE is allowed to access a cell and definesscheduling of other SIBs. SIBs other than theSystemInformationBlockType1 are carried in SystemInformation (SI)messages and mapping of SIBs to the SI messages is flexibly configurableby schedulingInfoList included in the SystemInformationBlockType1. EachSIB is contained only in a single SI message. Only SIBs having the samescheduling requirement (periodicity) can be mapped to the same SImessage. The SystemInformationBlockType2 is always mapped to the SImessage that corresponds to the first entry in the list of SI messagesin schedulingInfoList. There may be multiple SI messages transmittedwith the same periodicity. The SystemInformationBlockType1 and all SImessages are transmitted on a DL-SCH.

The MIB uses a fixed schedule with a periodicity of 40 ms andrepetitions made within 40 ms. The first transmission of the MIB isscheduled in subframe #0 of radio frames for which the SFN mod 4=0, andrepetitions are scheduled in subframe #0 of all other radio frames.

The SystemInformationBlockType1 uses a fixed schedule with a periodicityof 80 ms and repetitions made within 80 ms. The first transmission ofthe SystemInformationBlockType1 is scheduled in subframe #5 of radioframes for which the SFN mod 8=0, and repetitions are scheduled insubframe #5 of all other radio frames for which SFN mod 2=0. A singlesystem information radio network temporary identifier (SI-RNTI) is usedto address the SystemInformationBlockType1 as well as all other SIBs.The SystemInformationBlockType1 configures an SI-window length and thetransmission periodicity for all other SIBs.

The SI messages are transmitted within periodically occurring SI-windowsusing dynamic scheduling. Each SI message is associated with aSI-window, and SI-windows of different SI messages do not overlap. Thatis, within one SI-window only the corresponding SI is transmitted. Thelength of the SI-window is common for all SI messages, and isconfigurable. Within the SI-window, the corresponding SI message can betransmitted a number of times in any subframe other than multicastbroadcast single frequency network (MBSFN) subframes, uplink subframesin time domain duplex (TDD), and subframe #5 of radio frames for whichSFN mod 2=0. The UE acquires the detailed time-domain scheduling (andother information, e.g. frequency-domain scheduling, used transportformat) from decoding an SI-RNTI on a PDCCH.

The eNB may schedule DL-SCH transmissions concerning logical channelsother than BCCH in the same subframe as used for the BCCH. The minimumUE capability restricts the BCCH mapped to DL-SCH, e.g. regarding themaximum rate. System information may also be provided to the UE by meansof dedicated signaling, e.g. upon handover.

FIG. 6 shows a change of change of system information.

Change of system information only occurs at specific radio frames, i.e.concept of a modification period is used. System information may betransmitted a number of times with the same content within amodification period, as defined by its scheduling. The modificationperiod boundaries are defined by SFN values for which SFN mod m=0, wherem is the number of radio frames comprising the modification period. Themodification period is configured by system information.

When a network changes (some of the) system information, it firstnotifies UEs about this change, i.e. this may be done throughout amodification period. In the next modification period, the networktransmits updated system information. Referring to FIG. 6, differenthatchings indicate different system information. Upon receiving a changenotification, the UE acquires new system information immediately fromthe start of the next modification period. The UE applies the previouslyacquired system information until the UE acquires the new systeminformation.

The paging message is used to inform UEs in RRC_IDLE and UEs inRRC_CONNECTED about a system information change. If the UE receives thepaging message including systemInfoModification, it knows that thesystem information will change at the next modification period boundary.Although the UE may be informed about changes in the system information,no further details are provided e.g. regarding which system informationwill change.

The SystemInformationBlockType1 includes a value tag,systemInfoValueTag, that indicates if a change has occurred in thesystem information, as described in Table 1. The UE may usesystemInfoValueTag, e.g. upon return from out of coverage, to verify ifthe previously stored system information is still valid. Additionally,the UE considers the stored system information to be invalid after 3hours from the moment it was successfully confirmed as valid, unlessspecified otherwise.

The UE verifies that the stored system information remains valid byeither checking systemInfoValueTag in the SystemInformationBlockType1after the modification period boundary, or attempting to findsystemInfoModification indication at least modificationPeriodCoeff timesduring the modification period in case no paging message is received, inevery modification period. If no paging message is received by the UEduring a modification period, the UE may assume that no change of thesystem information will occur at the next modification period boundary.If the UE in RRC_CONNECTED, during the modification period, receives onepaging message, it may deduce from the presence/absence ofsystemInfoModification whether a change of the system information willoccur in the next modification period or not.

FIG. 7 shows a system information acquisition procedure.

A UE applies a system information acquisition procedure to acquire anAS- and NAS-system information that is broadcasted by an E-UTRAN. Thesystem information acquisition procedure applies to UEs in RRC_IDLE andUEs in RRC_CONNECTED.

Referring to FIG. 7, at step S50, a UE receives a MIB from an E-UTRAN.At step S51, the UE receives a SystemInformationBlockType1 from theE-UTRAN. At step S52, the UE receives system information from theE-UTRAN.

FIG. 8 shows an RRC connection establishment procedure. It may bereferred to Section 5.3.3 of 3GPP TS 36.331 V11.1.0 (2012-09). Thepurpose of this procedure is to establish an RRC connection. The RRCconnection establishment may involve SRB1 establishment. The RRCconnection establishment procedure is also used to transfer the initialNAS dedicated information/message from the UE to the E-UTRAN. TheE-UTRAN may apply the RRC connection establishment procedure toestablish SRB1 only.

Referring to FIG. 8, at step S60, the UE transmits an RRC connectionrequest (RRCConnectionRequest) message to the E-UTRAN. At step S61, theE-UTRAN transmits an RRC connection setup (RRCConnectionSetup) messageto the UE. At step S62, the UE transmits an RRC connection setupcomplete (RRCConnectionSetupComplete) message to the E-UTRAN.

Access class barring (ACB) is described below. It may be referred toSection 4.3.1 of 3GPP TS 22.011 V10.3.0 (2011-03).

If the UE is a member of at least one access class which corresponds tothe permitted classes as signaled over the air interface, and the accessclass is applicable in the serving network, access attempts are allowed.Additionally, in the case of the access network being UTRAN the servingnetwork can indicate that UEs are allowed to respond to paging andperform location registration, even if their access class is notpermitted. Otherwise, access attempts are not allowed. Also, the servingnetwork can indicate that UEs are restricted to perform locationregistration, although common access is permitted. If the UE respondedto paging, it shall follow the normal defined procedures and react asspecified to any network command.

Access classes are applicable as follows:

-   -   Classes 0-9: Home and visited public land mobile networks        (PLMNs);    -   Classes 11 and 15: Home PLMN only if the equivalent home PLMN        (EHPLMN) list is not present or any EHPLMN;    -   Classes 12, 13, 14: Home PLMN and visited PLMNs of home country        only.

Any number of these classes may be barred at any one time.

The following is the requirements for enhanced access control onE-UTRAN.

-   -   The serving network shall be able to broadcast mean durations of        access control and barring rates (e.g. percentage value) that        commonly applied to access classes 0-9 to the UE. The same        principle as in UMTS is applied for Access Classes 11-15.    -   The E-UTRAN shall be able to support access control based on the        type of access attempt (i.e. mobile originating data or mobile        originating signaling), in which indications to the UEs are        broadcasted to guide the behavior of UE. The E-UTRAN shall be        able to form combinations of access control based on the type of        access attempt, e.g. mobile originating and mobile terminating,        mobile originating, or location registration. The ‘mean duration        of access control’ and the barring rate are broadcasted for each        type of access attempt (i.e. mobile originating data or mobile        originating signaling).    -   The UE determines the barring status with the information        provided from the serving network, and perform the access        attempt accordingly. The UE draws a uniform random number        between 0 and 1 when initiating connection establishment and        compares with the current barring rate to determine whether it        is barred or not. When the uniform random number is less than        the current barring rate and the type of access attempt is        indicated allowed, then the access attempt is allowed;        otherwise, the access attempt is not allowed. If the access        attempt is not allowed, further access attempts of the same type        are then barred for a time period that is calculated based on        the ‘mean duration of access control’ provided by the network        and the random number drawn by the UE.

Extended access barring (EAB) is described below. It may be referred toSection 4.3.4 of 3GPP TS 22.011 V10.3.0 (2011-03).

The following requirements apply for EAB:

-   -   The UE is configured for EAB by the HPLMN.    -   EAB shall be applicable to all 3GPP radio access technologies.    -   EAB shall be applicable regardless of whether the UE is in a        home or a visited PLMN.    -   A network may broadcast EAB information.    -   EAB information shall define whether EAB applies to UEs within        one of the following categories:

a) UEs that are configured for EAB;

b) UEs that are configured for EAB and are neither in their HPLMN nor ina PLMN that is equivalent to it;

3) UEs that are configured for EAB and are neither in the PLMN listed asmost preferred PLMN of the country where the UE is roaming in theoperator-defined PLMN selector list on the SIM/USIM, nor in their HPLMNnor in a PLMN that is equivalent to their HPLMN

-   -   EAB information shall also include extended barring information        for access classes 0-9.    -   A UE configured for EAB shall use its allocated access        class(es), when evaluating the EAB information that is broadcast        by the network, in order to determine if its access to the        network is barred.    -   If a UE that is configured for EAB initiates an emergency call        or is a member of an access class in the range 11-15 and that        Access Class is permitted by the network, then the UE shall        ignore any EAB information that is broadcast by the network.    -   If the network is not broadcasting the EAB information, the UE        shall be subject to access barring.    -   If the EAB information that is broadcast by the network does not        bar the UE, the UE shall be subject to access barring.

The SystemInformationBlockType14 information element (IE) contains theEAB parameters. Table 1 shows an example of theSystemInformationBlockType14 IE.

TABLE 1 -- ASN1START SystemInformationBlockType14-r11 ::= SEQUENCE {eab-Param-r11 CHOICE { eab-Common-r11 EAB-Config-r11,eab-PerPLMN-List-r11 SEQUENCE (SIZE (1..6)) OF EAB-ConfigPLMN-r11 }OPTIONAL, -- Need OR lateNonCriticalExtension OCTET STRING OPTIONAL, --Need OP ... } EAB-ConfigPLMN-r11 ::= SEQUENCE { eab-Config-r11EAB-Config-r11 OPTIONAL -- Need OR } EAB-Config-r11 ::= SEQUENCE {eab-Category-r11 ENUMERATED {a, b, c, spare}, eab-BarringBitmap-r11 BITSTRING (SIZE (10)) } -- ASN1STOP

Change of EAB parameters can occur at any point in time. The EABparameters are contained in SystemInformationBlockType14. The pagingmessage is used to inform EAB capable UEs in RRC_IDLE about a change ofEAB parameters or that the SystemInformationBlockType14 is no longerscheduled. If the UE receives the paging message including theeab-ParamModification, it shall acquire the SystemInformationBlockType14according to schedulingInfoList contained inSystemInformationBlockType1. If the UE receives the paging messageincluding the eab-ParamModification while it is acquiring theSystemInformationBlockType14, the UE shall continue acquiring theSystemInformationBlockType14 based on the previously acquiredschedulingInfoList until it re-acquires schedulingInfoList in theSystemInformationBlockType1. That is, if in RRC_IDLE, theeab-ParamModification is included and the UE is EAB capable, the UEre-acquire the SystemInformationBlockType14 using the system informationacquisition procedure.

Table 2 shows an example of the paging message.

TABLE 2 -- ASN1START Paging ::= SEQUENCE { pagingRecordListPagingRecordList OPTIONAL, -- Need ON systemInfoModification ENUMERATED{true} OPTIONAL, -- Need ON etws-Indication ENUMERATED {true}OPTIONAL,-- Need ON nonCriticalExtension Paging-v890-IEs OPTIONAL }Paging-v890-IEs ::= SEQUENCE { lateNonCriticalExtension OCTET STRINGOPTIONAL, -- Need OP nonCriticalExtension Paging-v920-IEs OPTIONAL }Paging-v920-IEs ::= SEQUENCE { cmas-Indication-r9 ENUMERATED {true}OPTIONAL, -- Need ON nonCriticalExtensionPaging-v11xy-IEs OPTIONAL }Paging-v11xy-IEs ::= SEQUENCE { eab-ParamModification-r11 ENUMERATED{true} OPTIONAL, -- Need ON nonCriticalExtension SEQUENCE { } OPTIONAL-- Need OP } PagingRecordList ::= SEQUENCE (SIZE (1..maxPageRec)) OFPagingRecord PagingRecord ::= SEQUENCE { ue-Identity PagingUE-Identity,cn-Domain ENUMERATED {ps, cs}, ... } PagingUE-Identity ::= CHOICE {s-TMSI S-TMSI, imsi IMSI, ... } IMSI ::= SEQUENCE (SIZE (6..21)) OFIMSI-Digit IMSI-Digit ::= INTEGER (0..9) -- ASN1STOP

Referring to Table 2, the paging message includes theeab-ParamModification field. If present, the eab-ParamModification fieldindicates EAB parameters, i.e. SIB14, modification.

EAB check is performed as follows. The UE shall:

1> if SystemInformationBlockType14 is present and includes theeab-Param:

2> if the eab-Common is included in the eab-Param:

3> if the UE belongs to the category of UEs as indicated in theeab-Category contained in eab-Common; and

3> if for the access class of the UE that with a value in the range 0 .. . 9, as stored on the USIM, the corresponding bit in theeab-BarringBitmap contained in eab-Common is set to one:

4> consider access to the cell as barred;

3> else:

4> consider access to the cell as not barred due to EAB;

2> else (the eab-PerPLMN-List is included in the eab-Param):

3> select the entry in the eab-PerPLMN-List corresponding to the PLMNselected by upper layers;

3> if the eab-Config for that PLMN is included:

4> if the UE belongs to the category of UEs as indicated in theeab-Category contained in eab-Config; and

4> if for the access class of the UE that with a value in the range 0 .. . 9, as stored on the USIM, the corresponding bit in theeab-BarringBitmap contained in eab-Config is set to one:

5> consider access to the cell as barred;

4> else:

5> consider access to the cell as not barred due to EAB;

3> else:

4> consider access to the cell as not barred due to EAB;

1> else:

2> consider access to the cell as not barred due to EAB;

According to the description above, the UE shall ensure that it hasvalid SystemInformationBlockType14 (if scheduled) before performing anaccess subject to EAB check. Therefore, the UE shall not initiate theRRC connection establishment subject to EAB until the UE has a validSystemInformationBlockType14 if broadcast. In addition, the UE maintainsa valid SystemInformationBlockType14 based on reading pagingnotifications. However, in a specific scenario, some ambiguity forreceiving EAB parameters may occur.

FIG. 9 shows an example of a method for receiving EAB parametersaccording to the conventional art.

Referring to FIG. 9, the UE maintains a validSystemInformationBlockType14 (hereinafter, SIB14) based on readingpaging notifications. It is assumed that UE paging cycles are longerthan a SIB14 periodicity. For example, in FIG. 9, the UE paging cycle is256 radio frames, and the SIB14 periodicity is 128 radio frames. The UE1and UE2 that monitor the same SIB14 use the same UE paging cycle to readthe paging message. However, the UE1 and UE2 have different pagingoccasions, and therefore, the UE1 reads the paging message before theUE2. In this case, as described in FIG. 9, the SIB14 may be transmittedbetween different paging occasions of the UE1 and UE2. Accordingly, theUE1 and UE2 may have different SIB14 including different EAB parameterseach other. In FIG. 9, different hatchings of SIB14 correspond to oldand updated EAB parameters (EAB info 1 and 2) in the SIB14. And, in FIG.9, different hatchings of the paging correspond to old and updatedeab-ParamModification in the paging message.

According to the scenario described in FIG. 9, the UE and eNB may applydifferent EAB parameters at a certain point of time, e.g. P2/P3 in FIG.9. That is, the UE1 apply the EAB parameter 1 (old EAB parameter), whilethe eNB broadcast the SIB14 including the EAB parameter 2 (updated EABparameter), at P2/P3 in FIG. 9. In addition, different UEs may applydifferent EAB parameters at a certain point of time, e.g. P1, P2/P3 inFIG. 9, because different UEs in RRC_IDLE maintains a valid SIB14 byreading paging notifications based on UE specific paging occasions. AtP1 in FIG. 9, the UE1 has a valid SIB14 including EAB parameter 1, butUE2 does not have a valid SIB14. At P2/P3 in FIG. 9, the UE1 apply theEAB parameter 1 (old EAB parameter), while the UE2 apply the EABparameter 2 (updated EAB parameter).

How each UE applies EAB parameters upon initiation of the RRC connectionestablishment, depending on initiation point, P1, P2/P3, is described indetail.

1) At P1 in FIG. 9, if the UE1/UE2 initiates the RRC connectionestablishment:

-   -   eNB: the EAB parameter 1 is still valid at P1 in the eNB. The        EAB parameter 1 will be updated to the EAB parameter 2 sooner or        later, though.    -   UE1: the stored EAB parameter 1 is valid in the UE1. So, upon        the RRC connection establishment, the UE1 applies EAB based on        the EAB parameter 1.    -   UE2: the stored EAB parameter is not available in the UE2. But,        the UE2 identifies eab-ParamModification in the paging message        before P1. Thus, whether the UE2 should apply EAB after reading        updated SIB14 or the UE2 does not apply EAB is not clear.

2) At P2 in FIG. 9, if the UE1/UE2 initiates the RRC connectionestablishment:

-   -   eNB: the EAB parameter 1 has been updated to the EAB parameter        2. The EAB parameter 1 is not valid, now.    -   UE1: the stored EAB parameter 1 is valid in the UE1. So, upon        the RRC connection establishment, the UE1 will apply EAB based        on the EAB parameter 1, because the UE1 maintains up-to-date        SIB14 not by directly reading every SIB14, but by relying on        paging notifications. Thus, there is mismatch between the UE1        and the eNB. Whether the UE1 should read the SIB14 before        applying EAB or the UE1 should apply EAB with the old EAB        parameter 1 is not clear. This problem occurs when the paging        discontinuous reception (DRX) cycle is longer than the SIB14        periodicity.    -   UE2: the stored EAB parameter 2 is valid in the UE2. So, upon        the RRC connection establishment, the UE2 applies EAB based on        the EAB parameter 2.

3) At P3 in FIG. 9, if the UE1/UE2 initiates the RRC connectionestablishment:

-   -   eNB: the EAB parameter 1 has been updated to the EAB parameter        2. The EAB parameter 1 is not valid, now.    -   UE1: the stored EAB parameter 1 is valid in the UE1. So, upon        the RRC connection establishment, the UE1 may apply EAB based on        the EAB parameter 1. However, the UE1 identifies        eab-ParamModification in the paging message before P3. Thus,        whether the UE1 should apply EAB after reading updated SIB14 or        the UE1 should apply EAB based on the old EAB parameter 1 is not        clear.    -   UE2: the stored EAB parameter 2 is valid in the UE2. So, upon        the RRC connection establishment, the UE2 applies EAB based on        the EAB parameter 2.

In summary, the following two cases should be clarified for the scenariodescribed in FIG. 9.

1) Case 1: if the UE has identified eab-ParamModification in the pagingmessage, it should be clarified that when the NAS layer of the UErequests the RRC connection establishment, whether the RRC layer of theUE should wait until acquiring updated SIB14 (to avoid potentialmismatch between the eNB and the UE), or the RRC layer of the UE shouldapply EAB immediately upon the request from the NAS layer of the UE.

2) Case 2: if the UE has no its paging occasion (i.e. no paging isreceived) following the recently scheduled SIB14, but if the UE knowsupcoming SIB14 schedule based on the SI periodicity, it should beclarified that when the NAS layer of the UE requests the RRC connectionestablishment, whether the RRC layer of the UE should wait and readupcoming SIB14 (to avoid potential mismatch between the eNB and the UE)before applying EAB, or the UE should apply EAB immediately upon therequest from the NAS layer of the UE.

Therefore, to solve the problems described above, how to receive EABparameters and how to apply EAB upon connection establishment accordingto embodiments of the present invention is described below.

For the case 1 described above, i.e. when the NAS layer of the UEinitiates the RRC connection establishment after receiving theeab-ParamModification in the paging message, but before receiving thecorresponding SIB14, since the UE shall not initiate the RRC connectionestablishment subject to EAB until the UE has a valid SIB14, the UE mayneed to wait and receive the SIB14 before applying EAB. However, if theUE has previously received SIB14, the UE may not make sure whether theUE will acquire updated EAB parameters or the same EAB parameters fromupcoming SIB 14.

Thus, the RRC layer of the UE may need to apply EAB immediately upon therequest from the NAS layer of the UE. That is, when the NAS layer of theUE initiates the RRC connection establishment after receiving theeab-ParamModification in the paging message, but before receiving thecorresponding SIB14 (in case that the UE has available EAB parameters),the RRC layer of the UE may not wait to acquire upcoming SIB14, i.e. mayapply available EAB parameters immediately, upon the request from theNAS layer of the UE. According to this embodiment of the presentinvention, the UE may initiate the RRC connection establishment subjectto EAB based on the old EAB parameters, even though SIB14 is updated inthe eNB. But, the old EAB parameters should be valid in the UE, becausethe UE relies on paging notification to maintain up-to-date SIB14. Theremay be mismatch between the UE and the eNB, though. In case that the UEhas no available EAB parameters at the cell, the RRC layer of the UEshall wait to acquire upcoming SIB14.

Alternatively, when the NAS layer of the UE initiates the RRC connectionestablishment after receiving the eab-ParamModification in the pagingmessage, but before receiving the corresponding SIB14, the RRC layer ofthe UE may wait to acquire upcoming SIB14 and then apply EAB afteracquiring SIB14. According to this embodiment of the present invention,the UE does not initiate the RRC connection establishment subject to EABuntil the UE has a valid SIB14. Namely, upon the connectionestablishment subject to EAB, every UE would need to postpone applyingEAB before acquiring upcoming SIB14. Therefore, mismatch between the UEand the eNB may be avoided. Usage of paging notification for EAB wouldbe undermined.

For the case 2 described above, when the NAS layer of the UE initiatesthe RRC connection establishment subject to EAB, if the UE has no itspaging occasion (i.e. no paging is received) following the recentlyscheduled SIB14, mismatch between the UE and the eNB occurs because thepaging DRX cycle is longer than the SIB14 periodicity, and also becausethe UE relies on paging notifications to monitor SIB14.

In this case, when the NAS layer of the UE initiates the RRC connectionestablishment subject to EAB, if the UE has no its paging occasion (i.e.no paging is received) following the recently scheduled SIB14 (in casethat UE has available EAB parameters), the RRC layer of the UE may notwait to acquire upcoming SIB14, i.e. apply available EAB parametersimmediately upon the request from the NAS layer of the UE. Since the UErelies on paging notifications, it seems to be unlikely that the UE waitto acquire upcoming SIB14 without paging notification, only due topotential SIB14 change. In case that the UE has no available EABparameters at the cell, the RRC layer of the UE shall wait to acquireupcoming SIB14.

Alternatively, when the NAS layer of the UE initiates the RRC connectionestablishment subject to EAB, if the UE has no its paging occasion (i.e.no paging is received) following the recently scheduled SIB14, the RRClayer of the UE may wait to acquire upcoming SIB14 and then apply EABafter acquiring SIB14.

Alternatively, the eNB may make sure that the paging DRX cycle is equalto or less than the SIB14 periodicity. That is, a cell configuration isrestricted in advance, and accordingly, the eNB could exclude the casethat the paging DRX cycle is longer than the SIB14 periodicity.

FIG. 10 shows an example of a method for receiving EAB parametersaccording to an embodiment of the present invention.

At step S100, the UE receives an EAB parameter. The EAB parameter may bereceived via the SIB14.

At step S110, the UE receives an EAB parameter modification. Thereceived EAB parameter is invalidated upon receiving the EAB parametermodification. The EAB parameter modification may be aneab-ParamModification field in the paging message.

At step S120, the UE waits for applying EAB until modified EAB parameteris received. That is, when the NAS layer of the UE initiates the RRCconnection establishment after receiving the eab-ParamModification inthe paging message, but before receiving the corresponding SIB14, theRRC layer of the UE shall wait to acquire upcoming SIB14.

At step S130, the UE receives the modified EAB parameter. The modifiedEAB parameter may also be received via the SIB14. Then, UE applies EABaccording to the modified EAB parameter, after acquiring SIB14.

UE behaviors, according to the embodiment of the present inventiondescribed in FIG. 10, are as follows.

1> if in RRC_IDLE, the eab-ParamModification is included and the UE isEAB capable:

2> consider SystemInformationBlockType14 invalid, if previouslyreceived;

2> re-acquire SystemInformationBlockType1 immediately, i.e., withoutwaiting until the next system information modification period boundary;

2> re-acquire SystemInformationBlockType14 using the system informationacquisition procedure;

According to the embodiment of the present invention described in FIG.10, the UE shall verify validity of SIB14 by receiving upcoming SIB14whenever the UE initiates the RRC connection establishment. Hence, uponinitiation of the RRC connection establishment subject to EAB at a cell,the UE shall postpone applying EAB before acquiring upcoming SIB14.Accordingly, there is no mismatch of valid SIB14 between the UE and thecell.

FIG. 11 is a block diagram showing wireless communication system toimplement an embodiment of the present invention.

An eNB 800 may include a processor 810, a memory 820 and a radiofrequency (RF) unit 830. The processor 810 may be configured toimplement proposed functions, procedures and/or methods described inthis description. Layers of the radio interface protocol may beimplemented in the processor 810. The memory 820 is operatively coupledwith the processor 810 and stores a variety of information to operatethe processor 810. The RF unit 830 is operatively coupled with theprocessor 810, and transmits and/or receives a radio signal.

A UE 900 may include a processor 910, a memory 920 and a RF unit 930.The processor 910 may be configured to implement proposed functions,procedures and/or methods described in this description. Layers of theradio interface protocol may be implemented in the processor 910. Thememory 920 is operatively coupled with the processor 910 and stores avariety of information to operate the processor 910. The RF unit 930 isoperatively coupled with the processor 910, and transmits and/orreceives a radio signal.

The processors 810, 910 may include application-specific integratedcircuit (ASIC), other chipset, logic circuit and/or data processingdevice. The memories 820, 920 may include read-only memory (ROM), randomaccess memory (RAM), flash memory, memory card, storage medium and/orother storage device. The RF units 830, 930 may include basebandcircuitry to process radio frequency signals. When the embodiments areimplemented in software, the techniques described herein can beimplemented with modules (e.g., procedures, functions, and so on) thatperform the functions described herein. The modules can be stored inmemories 820, 920 and executed by processors 810, 910. The memories 820,920 can be implemented within the processors 810, 910 or external to theprocessors 810, 910 in which case those can be communicatively coupledto the processors 810, 910 via various means as is known in the art.

In view of the exemplary systems described herein, methodologies thatmay be implemented in accordance with the disclosed subject matter havebeen described with reference to several flow diagrams. While forpurposed of simplicity, the methodologies are shown and described as aseries of steps or blocks, it is to be understood and appreciated thatthe claimed subject matter is not limited by the order of the steps orblocks, as some steps may occur in different orders or concurrently withother steps from what is depicted and described herein. Moreover, oneskilled in the art would understand that the steps illustrated in theflow diagram are not exclusive and other steps may be included or one ormore of the steps in the example flow diagram may be deleted withoutaffecting the scope and spirit of the present disclosure.

What is claimed is:
 1. A method for applying extended access barring (EAB) upon connection establishment by a user equipment (UE) in a wireless communication system, the method comprising: acquiring, by a radio resource control (RRC) layer of the UE, a system information block (SIB)-14 from an eNodeB (eNB); receiving, by the RRC layer of the UE, a paging message including an EAB parameter modification from the eNB, wherein the previously acquired SIB-14 is invalidated upon receiving the paging message including the EAB parameter modification; receiving, by the RRC layer of the UE, a request of an RRC connection establishment from an upper layer; re-acquiring, by the RRC layer of the UE, the SIB-14 from the eNB; and applying, by the RRC layer of the UE, EAB for the RRC connection establishment according to the re-acquired SIB-14.
 2. The method of claim 1, wherein the previously acquired SIB-14 includes EAB parameters.
 3. The method of claim 1, wherein the EAB parameter modification indicates that EAB parameters are to be modified.
 4. The method of claim 1, wherein the re-acquired SIB-14 includes modified EAB parameters.
 5. The method of claim 1, wherein the upper layer is a non-access stratum (NAS) layer of the UE.
 6. The method of claim 1, further comprising waiting, by the RRC layer of the UE, for re-acquiring the SIB-14, before re-acquiring a second SIB-14.
 7. The method of claim 1, wherein the re-acquiring the SIB-14 comprises: acquiring, by the RRC layer of the UE, a SIB-1, which defines a scheduling of the SIB-14, immediately without waiting until a next system information modification period boundary; and re-acquiring, by the RRC layer of the UE, the SIB-14 according to the scheduling by the SIB-1.
 8. The method of claim 1, wherein the UE is in an RRC idle state.
 9. A user equipment (UE) in a wireless communication system, the UE comprising: a memory; a radio frequency (RF) unit; and a processor, coupled to the memory and the RF unit, that: controls the RF unit to acquire, by a radio resource control (RRC) layer of the UE, a system information block (SIB)-14 from an eNodeB (eNB); controls the RF unit to receive, by the RRC layer of the UE, a paging message including an extended access barring (EAB) parameter modification from the eNB, wherein the previously acquired SIB-14 is invalidated upon receiving the paging message including the EAB parameter modification; controls the RF unit to receive, by the RRC layer of the UE, a request of an RRC connection establishment from an upper layer; controls the RF unit to re-acquire, by the RRC layer of the UE, the SIB-14 from the eNB; and applies, by the RRC layer of the UE, EAB for the RRC connection establishment according to the re-acquired SIB-14.
 10. The UE of claim 9, wherein the previously acquired SIB-14 includes EAB parameters.
 11. The UE of claim 9, wherein the EAB parameter modification indicates that EAB parameters are to be modified.
 12. The UE of claim 9, wherein the re-acquired SIB-14 includes modified EAB parameters.
 13. The UE of claim 9, wherein the upper layer is a non-access stratum (NAS) layer of the UE.
 14. The UE of claim 9, wherein the processor further waits, by the RRC layer of the UE, for re-acquiring the SIB-14, before re-acquiring a second SIB-14.
 15. The UE of claim 9, wherein the re-acquiring the SIB-14 comprises: acquiring, by the RRC layer of the UE, a SIB-1, which defines a scheduling of the SIB-14, immediately without waiting until a next system information modification period boundary; and re-acquiring, by the RRC layer of the UE, the SIB-14 according to the scheduling by the SIB-1.
 16. The UE of claim 9, wherein the UE is in an RRC idle state. 